Over the years, many methods and apparatuses for manufacturing various bags, pouches and sealed packages have been devised. An example of a method and apparatus for manufacturing tea bags in disclosed in U.S. Pat. No. 4,262,473, which issued to Arthur A. Brooke on Apr. 21, 1981. In the Brooke method, a porous web is formed into a flattened closed tube as a continuous stream of tea product is introduced therewithin. The flattened tube filled with tea product first travels generally horizontally and means are provided to pinch the tube closed at predetermined intervals therealong. The pinching means are adapted to maintain the tube in its pinched condition as the tube is then moved vertically, thereby causing the tea product contained therein to migrate downwardly under gravity creating a voided area immediately below each pinch line. The porous tube is then heat sealed transversely along the voided areas of the tube. Further means are provided to separate the successive sections from the tube to form individual tea bags or groups of such bags.
U.S. Pat. No. 3,498,019, which issued to J. M. Rait on Mar. 3, 1970, also discloses a method and apparatus for forming sealed packages. The Rait sealed packages are formed from thermoplastic material wherein predetermined amounts of product are dosed onto the upper surface of a lower thermoplastic sheet in a predetermined pattern. Thereafter, a second thermoplastic sheet is brought in parallel to the first sheet and the two sheets are heat sealed together by a heated compartmentalized rotating cylinder. The movement of the upper and lower plastic sheets is synchronized with the rotational movement of the heated compartmentalized cylinder such that the compartments on the surface of the cylinder are positioned over the deposited product as the sheets are moved below the rotating cylinder.
A method of packaging predetermined volumes of incoherent product is disclosed in U.S. Pat. No. 3,813,848, which issued on June 4, 1974 to Andrea Romagnoli. The Romagnoli process utilizes a rotary dispensing drum having batching recesses formed therein to deposit predetermined doses of incoherent material onto the upper surface of a moving web of packaging material. A second band of wrapping material is thereafter bonded to the upper surface of the first sheet of material to cover the heaps of product deposited thereon. A similar volumetric batching device is shown in U.S. Pat. No. 4,437,294, which also issued to Andrea Romagnoli on Mar. 20, 1984. U.S. Pat. No. 4,404,787, which issued to G. Hazelwood on Sept. 20, 1983, similarly discloses a machine for packaging tea which includes a rotary dispensing drum which deposits tea in predetermined piles on a lower web and, thereafter, seals an upper web of packaging material onto the upper surface of the lower web about the perimeter of each pile. Individual tea bags are then separated from one another by a cutter.
A method of manufacturing an infusion package with an expandable bottom is taught in U.S. Pat. No. 2,571,138, which issued to H. O. Irmscher on Oct. 16, 1951. The Irmscher method includes folding a porous sheet of web material in half, then clamping the two parallel open sides by a pair of pincher jaws thereby creating a bag-like structure having an open top. A measured quantity of infusion product is then placed in the bag through its open top, and, thereafter, the top opening and the transversely extending side portions are heat sealed to form a closed pouch. A tag and string handle are then added to each bag by a separate operation.
A soap powder package heat sealed about its periphery and including additional heat seals delineating predetermined compartments in such package is shown in U.S. Pat. No. 4,433,783, which issued to R. H. Dickinson on Feb. 28, 1984. The Dickinson package includes a pair of cooperating front and rear heat sealable panels arranged on opposite sides of the soap powder which is spread out as a layer therebetween. The panels are heat sealed along their peripheral edges to form a storage compartment for the soap, and, thereafter, a plurality of additional heat seals are made to divide the storage compartment into a series of subcompartments to minimize shifting of the powder stored therewithin during handling. Dickinson teaches that the additional heat seals within the storage compartment can be made despite the presence of soap powder interposed between the heat sealable panels.
A method and apparatus for making sanitary napkins or the like is disclosed in U.S. Pat. No. 2,073,329, which issued to C. P. Winter on Mar. 9, 1937. In the Winter process a rotatable wheel having screened inlets connected to a source of suction collects cotton fibers in a predetermined pattern and deposits those cotton fibers on a gauze web moving along the bottom edge of the first rotating wheel. The gauze web is then moved to a second rotating wheel, and as the gauze web is rotated about the periphery of the second rotating wheel, additional loose absorbent material is forced in a predetermined pattern onto the previously deposited loose cotton patches to selectively build up a wad or pad on the web. The gauze web is thereafter forwarded with its built up pads for further processing.
Despite the great amount of prior work done with regard to improving the process of making laminated products having inner compartments containing quantities of inner product, as evidenced by some of the above-described patents, there remain problems in efficiently producing such laminated products with high quality and at high speeds on automatic equipment. For example, with equipment and methods currently available in the industry, accurate high speed dosing of predetermined amounts of granular material is messy, unreliable and relatively slow.